Gearbox Oil Change

[duden]

When purchasing my 2004 C5 Hdi diesel I was told that the oil was in for life.

I would have thought that it should be changed by now (at 52000 miles), although there is no gearbox whine. Since I intend to do at least 100,000 miles should I change it?

I am thinking of using a fully synthetic oil. In my Renault (Rubbish) 21 (17 years of excellent service),I used the recommended oil and it was then very stiff in cold weather. I replaced it with a multigrade which cured it. The gearbox was very quiet and smooth.

[Johndouglas]

I changed my late Xantia's gear oil when it was 40000 miles from new. The oil that came out was quite gritty. Worth doing I thought.